Read a project data file

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations declare readOnlyHint=true and openWorldHint=false, so safety is already covered, and the description adds a genuinely useful trait annotations cannot express: large files are truncated, with the mitigation (filter by keys or prefix). It still doesn't say what an error looks like for a missing file or whether truncation is silent versus flagged, so it is strong but not exhaustive.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Two short sentences with zero padding, and the truncation warning is placed where it matters. The opening noun fragment is slightly clipped — a verb would make it read better — but nothing is wasted.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With an output schema present, return values need no explanation, and the read-only annotation carries the safety profile; the description covers the one thing neither structured field expresses (truncation). The gap is the missing link to cm_list, which the schema alludes to with "as cm_list returns it" but the description never states.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so the baseline is 3, but the description goes one step further by tying the optional keys/prefix parameters to a concrete consequence (truncation avoidance), which explains why an agent should use them. The example prefix formats themselves live in the schema, so no further compensation is needed.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description names the resource precisely — CarMaker infofile key/value pairs — but uses a noun fragment with no verb, so the action (reading a file's contents) is only inferable from the title. It also never distinguishes itself from siblings like cm_list or cm_edit, leaving the agent to work out that this one fetches content rather than file names or writes.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

"Large files are truncated: filter by keys or prefix" tells the agent how to avoid truncation, but there is no guidance on when to choose this tool over cm_list (to obtain the file name) or cm_edit (to modify it). No prerequisites, no exclusions, and no named alternative — usage is left entirely to inference.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.